253 research outputs found
Measuring the Applications of the Subject Doctorate to Academic Librarianship in North America
This work records and discusses the results of an anonymous web-based survey administered in January and February of 2019 to academic librarians with subject doctorates (i.e. PhDs in disciplines outside of library and information science) employed in North America. Respondents answered a mixture of quantitative and qualitative questions about the fields of their PhDs, their MLSs or equivalent degrees, their current positions in academic libraries, and the relevancy of their doctoral training to their current positions. According to the principal finding of this study, a majority of those librarians surveyed apply their doctoral training directly to their current positions in academic libraries, albeit at lower rates than those observed in the preceding decade. Statistically significant correlations were found between the relevancy of respondents’ doctoral training to their current positions, the accreditation status of their MLS or equivalent, and the year they began their current positions.Master of Science in Library Scienc
Gateways as inter-modal nodes in different ages: The Venetian region, eighteenth to twentieth centuries
This paper focuses on the theoretical implications of a regional case studyfor the analysis of transportation networks and gateway functions. Thestarting point is the result of a research on the changing role of gateways,and on the relocation of the gateway function from one city to a series ofcities in the Venetian region from the eighteenth to the twentieth century.Against this evolution, I test the validity and usefulness of a definition of thegateway as a point of inter-modal exchange for its historical interpretation.Changing transport technologies involve different organisations of inter-modal exchanges, and imply more or less intense economic functions ofgateway cities. These changes intertwine with political events and deci-sions, and more general economic changes: they could at the same time beread as an effect of these transformations, and as a causal factor. From this perspective, a study of intermodality shows to be useful to shed new lighton specific changes in the structure of urban hierarchie
Mast cell tryptase stimulates myoblast proliferation; a mechanism relying on protease-activated receptor-2 and cyclooxygenase-2
<p>Abstract</p> <p>Background</p> <p>Mast cells contribute to tissue repair in fibrous tissues by stimulating proliferation of fibroblasts through the release of tryptase which activates protease-activated receptor-2 (PAR-2). The possibility that a tryptase/PAR-2 signaling pathway exists in skeletal muscle cell has never been investigated. The aim of this study was to evaluate whether tryptase can stimulate myoblast proliferation and determine the downstream cascade.</p> <p>Methods</p> <p>Proliferation of L6 rat skeletal myoblasts stimulated with PAR-2 agonists (tryptase, trypsin and SLIGKV) was assessed. The specificity of the tryptase effect was evaluated with a specific inhibitor, APC-366. Western blot analyses were used to evaluate the expression and functionality of PAR-2 receptor and to assess the expression of COX-2. COX-2 activity was evaluated with a commercial activity assay kit and by measurement of PGF<sub>2</sub>α production. Proliferation assays were also performed in presence of different prostaglandins (PGs).</p> <p>Results</p> <p>Tryptase increased L6 myoblast proliferation by 35% above control group and this effect was completely inhibited by APC-366. We confirmed the expression of PAR-2 receptor <it>in vivo </it>in skeletal muscle cells and in satellite cells and <it>in vitro </it>in L6 cells, where PAR-2 was found to be functional. Trypsin and SLIGKV increased L6 cells proliferation by 76% and 26% above control, respectively. COX-2 activity was increased following stimulation with PAR-2 agonist but its expression remained unchanged. Inhibition of COX-2 activity by NS-398 abolished the stimulation of cell proliferation induced by tryptase and trypsin. Finally, 15-deoxy-Δ-<sup>12,14</sup>-prostaglandin J<sub>2 </sub>(15Δ-PGJ<sub>2</sub>), a product of COX-2-derived prostaglandin D<sub>2</sub>, stimulated myoblast proliferation, but not PGE<sub>2 </sub>and PGF<sub>2</sub>α.</p> <p>Conclusions</p> <p>Taken together, our data show that tryptase can stimulate myoblast proliferation and this effect is part of a signaling cascade dependent on PAR-2 activation and on the downstream activation of COX-2.</p
Augmentation of keratinocyte differentiation by the epidermal mitogen, 8-bromo-cAMP
The effect of the epidermal mitogen, 8-bromo-cAMP, on keratinocyte differentiation was studied. A 3 x 10-4 M dose of 8-bromo-cAMP was added to primary neonatal mouse epidermal keratinocyte cultures that slowly proliferate, stratify and differentiate over 2-3 weeks time. [3H]Thymidine autoradiography coupled with an NH4Cl plus reducing agent technic which separates basal and differentiating keratinocytes was used to determine the target cell for the 8-bromo-cAMP mitogenic effect. A histologic stain and a four buffer protein extraction protocol, in conjunction with PAGE and fluorographic technics, were used to assess the differentiation of the cultures. The data indicated that 8-bromo-cAMP primarily stimulated the proliferation of the basal cell monolayer. Simultaneous with the mitogenic effect was an increase in the production of keratohyalin granule, keratin and cell envelope proteins, which are specific markers of epidermal differentiation. The results indicate that keratinocytes stimulated by the epidermal mitogen 8-bromo-cAMP simultaneously express differentiation-related processes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25070/1/0000501.pd
CREB Is Activated by Muscle Injury and Promotes Muscle Regeneration
The cAMP response element binding protein (CREB) plays key roles in differentiation of embryonic skeletal muscle progenitors and survival of adult skeletal muscle. However, little is known about the physiologic signals that activate CREB in normal muscle. Here we show that CREB phosphorylation and target genes are induced after acute muscle injury and during regeneration due to genetic mutation. Activated CREB localizes to both myogenic precursor cells and newly regenerating myofibers within regenerating areas. Moreover, we found that signals from damaged skeletal muscle tissue induce CREB phosphorylation and target gene expression in primary mouse myoblasts. An activated CREB mutant (CREBY134F) potentiates myoblast proliferation as well as expression of early myogenic transcription factors in cultured primary myocytes. Consistently, activated CREB-YF promotes myoblast proliferation after acute muscle injury in vivo and enhances muscle regeneration in dystrophic mdx mice. Our findings reveal a new physiologic function for CREB in contributing to skeletal muscle regeneration
A Proof Theoretic Analysis of Intruder Theories
We consider the problem of intruder deduction in security protocol analysis:
that is, deciding whether a given message M can be deduced from a set of
messages Gamma under the theory of blind signatures and arbitrary convergent
equational theories modulo associativity and commutativity (AC) of certain
binary operators. The traditional formulations of intruder deduction are
usually given in natural-deduction-like systems and proving decidability
requires significant effort in showing that the rules are "local" in some
sense. By using the well-known translation between natural deduction and
sequent calculus, we recast the intruder deduction problem as proof search in
sequent calculus, in which locality is immediate. Using standard proof
theoretic methods, such as permutability of rules and cut elimination, we show
that the intruder deduction problem can be reduced, in polynomial time, to the
elementary deduction problem, which amounts to solving certain equations in the
underlying individual equational theories. We show that this result extends to
combinations of disjoint AC-convergent theories whereby the decidability of
intruder deduction under the combined theory reduces to the decidability of
elementary deduction in each constituent theory. To further demonstrate the
utility of the sequent-based approach, we show that, for Dolev-Yao intruders,
our sequent-based techniques can be used to solve the more difficult problem of
solving deducibility constraints, where the sequents to be deduced may contain
gaps (or variables) representing possible messages the intruder may produce.Comment: Extended version of RTA 2009 pape
Genetic variation and exercise-induced muscle damage: implications for athletic performance, injury and ageing.
Prolonged unaccustomed exercise involving muscle lengthening (eccentric) actions can result in ultrastructural muscle disruption, impaired excitation-contraction coupling, inflammation and muscle protein degradation. This process is associated with delayed onset muscle soreness and is referred to as exercise-induced muscle damage. Although a certain amount of muscle damage may be necessary for adaptation to occur, excessive damage or inadequate recovery from exercise-induced muscle damage can increase injury risk, particularly in older individuals, who experience more damage and require longer to recover from muscle damaging exercise than younger adults. Furthermore, it is apparent that inter-individual variation exists in the response to exercise-induced muscle damage, and there is evidence that genetic variability may play a key role. Although this area of research is in its infancy, certain gene variations, or polymorphisms have been associated with exercise-induced muscle damage (i.e. individuals with certain genotypes experience greater muscle damage, and require longer recovery, following strenuous exercise). These polymorphisms include ACTN3 (R577X, rs1815739), TNF (-308 G>A, rs1800629), IL6 (-174 G>C, rs1800795), and IGF2 (ApaI, 17200 G>A, rs680). Knowing how someone is likely to respond to a particular type of exercise could help coaches/practitioners individualise the exercise training of their athletes/patients, thus maximising recovery and adaptation, while reducing overload-associated injury risk. The purpose of this review is to provide a critical analysis of the literature concerning gene polymorphisms associated with exercise-induced muscle damage, both in young and older individuals, and to highlight the potential mechanisms underpinning these associations, thus providing a better understanding of exercise-induced muscle damage
Stress hyperglycaemia in the acute care setting
Introduction:
Stress hyperglycaemia (SH), defined as transient hyperglycaemia during illness, is seen in up to 50% of inpatients and may progress to glucose intolerance in a significant proportion. SH is also associated with increased mortality. Despite this, there is no consensus on definition and management. Existing work focuses on single disease groups, frequently reporting adverse outcomes and variable success with therapies. There is, however, a scarcity of work profiling individuals with SH in detail. It is hoped that this approach may contribute to individualised management and improved outcomes for people with the condition.
Methods:
The central hypotheses of this work focus on metabolic profiling and were examined through a prospective observational study. Participants were allocated into study groups based on glucose levels. A 30-day follow-up was organised for people with SH. Novel biomarkers, tools and a diabetes risk calculator were employed to provide the most detailed profile currently available of individuals with stress hyperglycaemia. Finally, results from the first multicentre trial to bear on the effect of metformin in SH are presented.
Results:
The prevalence of SH was 34% and 31% in prospective (n=62) and metformin (n=52) studies respectively. People with SH had lower fasting insulin levels and insulin resistance. Otherwise, few differences were found. Metabolic profile, glycaemic variability, and HbA1c values were similar in both groups. Metabolic abnormalities and marked glycaemic excursions were also seen in both groups. Metformin was well tolerated but did not result in significantly reduced glucose variability or levels during the study period.
Conclusions:
People with SH do not appear to be phenotypically different from people without the condition. Marked hyper- and hypoglycaemia are common in hospital patients despite apparent normal glucose levels. Increased vigilance as well as timely and appropriate interventions could significantly improve outcomes for these individuals.Open Acces
The efficacy of liability under the rule in Rylands v Fletcher in construction industry in Malaysia
Rylands v Fletcher is under the law of torts which regulates at common law of activities affecting individual rights in or over real property and protects public rights. Rylands v Fletcher is a classic case in United Kingdom. which handling cases of environmental liability and practicing strict liability. It is quite popular because it functions as a mechanism of environmental protection. In Malaysia the application of the rule of Rylands v Fletcher was developed more than three decades ago and the rule has been applied in a number of cases. Recently the function of the rule since its inceptions been progressively deteriorate and restricted in its application from within and the area in which it applied to oblige liability gradually diminished. The enormous issue can be lift up under this research is, should a Malaysian court continue to apply the rule in Rylands v Fletcher without amendment to the requirements of the liability, because the capability of the liability of the rule originally is not adequate to familiarize with the growing figure of damages and to speed up the court case. The objectives of this research are to determine the environmental cases in Malaysia and the associated issues and to determine the applicability of Rylands v Fletcher in environmental cases in Malaysian Construction Industry. The scope of the research is focus on Malaysian cases only where have been tested from the court held from the year of 1960 until 2006. The findings of this research suggested that with the rising figure of environmental cases in Construction Industry therefore, need to speed up the court cases to lessen the burden of the plaintiff in order for them to secure some kind of monetary compensation for damages to people’s belongings and with this approach the polluters will definitely be answerable for all damages. To speed up the court case another finding suggested that need some modification to the rule to make it more effective. Applicability of the rule of Rylands v Fletcher in Malaysia with the new version of additional ingredient that is ‘foreseeability’. With this new addition as an essential component of liability to the rule of Rylands v Fletcher, the judges, lawyers, legal skills and proficiency would perform the theory of strict liability in the expanding figure of environmental cases in order to guarantee that those cases are appropriately developed in court without any offensive interruption
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